Identification of the sex pheromone of Nesidiocoris tenuis,a damaging pest of commercial tomato

Nesidiocoris tenuis (Reuter) (Heteroptera: Miridae) is a tropical mirid bug. Although N. tenuis predates important insect pests, especially whitefly and larvae of Tuta absoluta, it also causes damage by feeding on tomato plants, particularly when prey populations decline. Feeding causes necrotic rings on stems and leaf petioles, flower abortion and punctures on fruits. In southern European countries, Nesidiocoris tenuis is used as a biocontrol agent in protected crops, including tomatoes however it is considered an invasive pest in the UK and its use as a biocontrol agent is not approved. Control requires application of pesticides incompatible with IPM programmes, leading to resurgence of whitefly populations and associated viruses, and disruption of other biocontrol systems such as the use of predatory mites against spider mites. This project identified, synthesised and field tested the sex pheromone of N. tenuis paving the way for the development of pheromone traps for better monitoring of pest numbers and more efficient use of control agents.

Aim: To identify the female-produced sex pheromone of Nesidiocoris tenuis and demonstrate attraction of male bugs to the pheromone in the laboratory and commercial crops.

Objectives:

• Rear unmated male and female N. tenuis for bioassay and identification work, and demonstrate existence of a female-produced sex pheromone attractive to male bugs.
• Make headspace collections of volatiles released by N. tenuis male and females.
• Analyse collections by gas chromatography linked to electroantennographic recording from the antennae of male N. tenuis to detect candidate pheromone components.
• Analyse collections by GC coupled to mass spectrometry (GS-MS) and other techniques as appropriate to identify candidate pheromone components.
• Synthesise candidate pheromone components.
• Formulate candidate pheromone components in suitable dispensers for laboratory and field bioassays.
• Demonstrate attraction of male N. tenuis to synthetic compounds in laboratory and field bioassays.